The present invention relates to polarization control in general. More particularly, the invention provides for the first time, a method and apparatus for complete polarization control of electromagnetic (EM) waves using photonic crystals. The novel apparatus utilizing the invention includes, for example, photonic-crystal-based transmission waveplates, polarizers, and reflection waveplates. These devices have tremendous advantages over the prior art: they can be much smaller than prior art devices, of the order of magnitude of one thousand times smaller; they can also be adjusted and modified to fit end uses more extensively than the prior art; and they can be scaled to any wavelength range including, but not limited, to the microwave, infrared, visible, and ultraviolet portions of the EM spectrum. It is also important that the birefringent properties of photonic crystals are related to the lattice geometry and indices of refraction of the constituent materials; thus, the birefringent and/or dispersive properties of photonic crystals can be tailored by adjusting the lattice geometry and size, as well as altering the constituent materials and their relative proportions.
Photonic crystal birefringence has a range of potential applications. For example, these and related photonic-crystal devices will be useful in laboratory equipment, and to control the flow of light in circuits and all-optical devices for communication and computing purposes.
Furthermore, the use of photonic crystal birefringence and dispersion can be utilized in nonlinear optics to achieve phase-matching. This will afford many advantages over conventional phase-matching techniques. For example, in the prior art, phase matching in nonlinear optical processes is typically accomplished with birefringent, nonlinear materials. Although there are many types of materials with optical nonlinearity, few are also sufficiently birefringent. However, a photonic crystal can be birefringent and/or dispersive even if its constituent materials are neither birefringent, nor dispersive; therefore, using a photonic crystal constructed from a material with optical nonlinearity, it is possible to achieve phase matching without a material that is intrinsically birefringent.
It is also possible to utilize photonic-crystal birefringence to couple two different modes (e.g., modes of polarization) for the purpose of creating an optical delay line. This type of delay line can in fact be created using any birefringent medium, which need not necessarily be photonic-crystal-based.
A primary object of the invention is to provide a method and apparatus for controlling and/or manipulating the polarization of electromagnetic (EM) waves with photonic crystals.
A further object is to provide a photonic crystal transmission waveplate capable of manipulating the polarization of light transmitted through the photonic crystal.
A further object is to provide a photonic crystal reflection waveplate capable of manipulating the polarization of light reflected by the crystal.
Another object of the invention is to provide a photonic crystal polarizer capable of reflecting one polarization and transmitting the other polarization (of a single wavelength), and which is not limited by Brewster's angle, so that the polarized reflected and transmitted beams can have any angle relative to the incident beam.
A further object is to provide a method of polarization control using photonic crystals for controlling the flow of light in circuits and all-optical devices used in laboratory equipment, communications, and computers.
Another object is to provide a method of polarization control using photonic crystals to achieve phase-matching in nonlinear optics.
Another object is to provide a method of creating a novel delay line for electromagnetic (EM) waves using energy transfer between different electromagnetic modes.
Other objects and advantages of the invention will become apparent from the following description and drawings wherein: